Control of Artificial Light for Plants

Abstract

A device of simulation and display was developed for monitoring the controlled spectral composition of artificial light for plants. The simulation was performed in the following manner:The spectral intensity at rated capacity is denoted by the function of wavelength, λ. Individual function, fi (λ), i=1, 2, …6, of six kinds of the lamps is coded in digital form on ROM in the function generator and is used to generate voltage value, Vfi (λ) . A dimming parameter ki is converted into voltage value, Vki in the potentiometer. The Vfi (λ) is multiplied by the Vki to produce voltage value corresponding to an optional spectral intensity of each kind of the lamps. These multiplied values of Vk1Vf1 (λ) , Vk2Vf2 (λ) , … and Vk6Vf6 (λ) are summed up in the summing amplifier to manipulate F (λ) which is displayed on the CRT as the spectral composition of combined light. The signals from potentiometers are also used as actuating signals in light control system.Thus, the change of spectral composition with the variation of each parameter was examined immediately on the CRT, and at the same time, the spectral composition was controlled. Experimental results demonstrate that the simulation method employed is satisfactory for the evaluation of the spectral composition, and the developed system makes it possible to monitor the spectral composition in artificial light control.